Impact of Long Term Production Systems on Greenhouse Gas Emissions.

Agriculture accounts for a large portion of land use worldwide.  In the U.S. specifically, the World Bank indicated that agriculture accounts for roughly 45% of land use.  Agriculture is estimated to contribute greatly to the output of one of the main greenhouse gases, nitrous oxide, which is suspected of contributing to climate change, contributing an estimated 59 percent to emissions. These large percentages are suspected to partially be due to one-third of nitrogen applied to cropping systems being utilized by the system while the additional two-thirds are lost to the environment.  With different agricultural practices contributing to these greenhouse gas emissions, finding how various production practices contribute to greenhouse gas emissions will help in the recommendation of best management practices to minimize gas emissions by agriculture in the southeastern U.S.  Field studies were conducted in 2013 and 2014 at the Center for Agricultural Farming Systems at the Cherry Research Farm in Goldsboro, NC.  Long-term plots of conventional no-till, conventional-tillage, conventional crop-hay, organic tillage, organic minimal tillage, and organic crop-hay systems were used to measure the flux of the greenhouse gases CO₂, CH₄, and N₂O, 24 to 48 hours after ~1.25 cm or more of rainfall, following USDA-ARS GRACEnet Project Protocols.  In each of the listed systems a weedy and weed-free subplot was sampled.  Contrasts were used to compare systems, herbicide use, and tillage.  Preliminary results indicated that tillage plays a significant role in gas emissions in cropping systems.